Need to hide or show a particular widget on a certain page ? Here are some wordpress plugins that allow you to control the display of widgets on selected pages or posts.
Learn how to add your own custom php code to functions.php without editing the file directly. Instead use a plugin to add the code and keep it across different themes.
Do you update your old posts to provide uptodate content. Then it can be useful to display the last modified date of a post in the content. This tells the user how recent the content is. This post shows you how to use a filter function to do the same.